RU2708426C2 - Drilling muds and method for production thereof - Google Patents

Abstract

FIELD: chemistry.

SUBSTANCE: group of inventions relates to drilling fluids and a method for production thereof. Method of producing drilling fluid involves oligomerisation of hex-1-ene to form oligomers, which include trimers and tetramers of hex-1-ene with ratio of trimer to tetramer of more than 1:1 and content of trimers of more than 30 wt. %, wherein oligomers are formed in the presence of acid-type catalysts; mixing said oligomers with linear olefins which include linear alpha-olefins and/or linear internal olefins with 6 to 30 carbon atoms. Drill mud obtained by said method contains linear olefins which include linear alpha-olefins and/or linear internal olefins with number of carbon atoms from 6 to 30; and oligomers, which include dimers, trimers, tetramers and/or heavier oligomers of olefins, wherein said oligomers include trimers and tetramers of hex-1-ene with ratio of trimer to tetramer greater than 1:1 and content of trimers more than 30 wt. % and where said oligomers include at least 50 mol percent trisubstituted olefin. Drilling fluid has pour point -10 °C or lower, biodegradation index 1.0 or lower, toxicity index 1.0 or lower, indicator in Marine BODIS test is at least 60 %, flash point is 110 °C or higher, content of olefins 90 wt. % or higher, viscosity less than 4 cSt at 40 °C, density from 0.78 to 0.83 g/ml and distribution coefficient in system octanol/water log Pow higher than 3.

EFFECT: technical result is low pour point, biodegradation and low toxicity of drilling mud.

24 cl, 8 dwg, 7 tbl, 14 ex

Description

[0001] This application claims priority to provisional application for US patent No. 61/990,371, filed May 8, 2014, the contents of which are fully incorporated into the present invention by reference.

[0002] The present invention provides a drilling fluid that includes olefins and oligomers. More specifically, the drilling fluid is characterized by a low pour point, good biodegradation and low toxicity.

BACKGROUND

[0003] Drilling fluids lubricate the components of the rig and carry bits of cuttings to the surface of the borehole. Conventional drilling fluids include hydrocarbons of diesel and kerosene fractions with low biodegradability and / or toxicity when used in environmentally sensitive areas, such as, for example, the sea. Synthetic drilling fluids are aimed at improving biodegradation, reducing toxicity and pour point. Recent changes in environmental legislation allow the discharge of certain classes of synthetic drilling fluids that meet specific environmental safety criteria. This increased need for drilling fluids that meet stringent biodegradation and toxicity requirements has led to a shortage of environmentally friendly flushing fluids. Even taking into account the technological improvements described above, there remains the need and desire to have drilling fluids with a low pour point and less polluting properties, such as biodegradation and low toxicity.

SUMMARY OF THE INVENTION

[0004] The drilling fluid contains linear olefins, which include linear alpha-olefins and / or linear olefins with an internal double bond (“internal” olefins) with carbon numbers from about 6 to about 30. Oligomers include dimers, trimers, tetramers and / or higher molecular weight oligomers of olefins. In this aspect, the number of carbon atoms in olefins is from about 4 to about 24, and the oligomers include at least about 50 mole percent of a trisubstituted olefin. The temperature of the fluidity loss of the drilling fluid is about -10 ° C or lower, and the biodegradation index is about 1.0 or less, the toxicity index is about 1.0 or less, the indicator in the Marine BODIS test (Biodegradability of Insoluble Substances, biodegradability of insoluble substances) by at least about 60%, a flash point of about 110 ° C or higher, the olefin content of 90 weight. % or higher, a viscosity lower than about 4 cSt at 40 ° C, a density of from about 0.78 to about 0.83 gram / ml, and a distribution coefficient in the octanol / water (log Pow) system of about 3.

[0005] A method for producing a drilling fluid comprises oligomerizing olefins with a number of carbon atoms in a molecule of from about 4 to about 24 to form oligomers, the oligomers (oligomeric portion) being formed in the presence of an acid catalyst. The method also includes mixing oligomers with linear olefins to form a drilling fluid.

BRIEF DESCRIPTION OF THE DRAWINGS

[0006] The above and other aspects, features, and advantages of certain aspects of this method will be more apparent based on the figures below.

[0007] Figure 1 presents a histogram of the toxicity index and biodegradation index of the compositions of Example 1A, Example 2 and Example 4;

[0008] Figure 2 shows dose-response curves of dose-effect toxicity for the composition of Example 4 and the reference material C1618;

[0009] Figure 3 presents a histogram of the toxicity index and biodegradation index of the compositions of Example 1A, Example 2, Example 3 and Example 5;

[0010] Figure 4 presents a histogram of the toxicity index and biodegradation index of the compositions of Example 1B, Example 2 and Example 6;

[0011] Figure 5 presents a histogram of the toxicity index and biodegradation index of the compositions of Example 7, Example 8 and Example 9;

[0012] Figure 6 presents a histogram of the toxicity index and biodegradation index of the compositions of Example 9, Example 11 and Example 12;

[0013] Figure 7 shows a histogram of the toxicity index and biodegradation index of the compositions of Example 9, Example 10 and Example 13; and

[0014] Figure 8 shows a histogram of the toxicity index and biodegradation index of the compositions of Example 7, Example 2C and Example 14.

DETAILED DESCRIPTION OF THE INVENTION

[0015] The following description is not intended to be limiting, but is given only for the purpose of describing the general principles of exemplary embodiments. The scope of the invention should be determined on the basis of the claims.

The present invention provides a drilling fluid suitable for use in environmentally sensitive areas. Drilling fluid undergoes preliminary examination in accordance with the recommendations of OSPAR 2000/4, as amended by the recommendations of OSPAR 2008/1 and 2010/4, 2012-05, with an indicator of at least 60% in the Marine BODIS test in accordance with the OECD guidelines (OECD ) for testing OECD 301A, B, C, D or F and is classified according to the OCNS classification to group D, either with a minimum toxicity in the aquatic environment> 100, in another aspect> 1000, or with a minimum toxicity of deposits> 1,000, and in another aspect > 10,000, in the absence of any warning about changes listed in the full list authorized products research center in the field of environmental protection, Fisheries and Aquaculture (CEFAS).

[0016] In another aspect, a drilling fluid is provided suitable for use in environmentally sensitive areas. Drilling fluid undergoes preliminary examination in accordance with the recommendations of OSPAR 2000/4, as amended by the recommendations of OSPAR 2008/1 and 2010/4, 2012-05, with an indicator of at least 60% in the Marine BODIS test in accordance with the OECD testing guidelines OECD 301A, B, C, D, or F and is classified according to the OCNS classification either to group E, with a minimum toxicity in the aquatic environment> 100, in another aspect> 1000, or with a minimum toxicity of deposits> 1,000, and in another aspect> 10,000, in the absence of any warning about changes listed in the full lists of Solutions Products Research Center in the field of Environment, Fisheries and Aquaculture (CEFAS).

[0017] In another aspect, the drilling fluid meets the following criteria: a flash point of at least 120 ° C as determined by ASTM D 93, kinematic viscosity at 40 ° C <3 centistokes, and Log Pow> 3 in OECD Test (OECD) 117 , and a density of 0.79-0.82 as determined by standard ASTM D 1298 method with an olefin content> 90%, in accordance with the requirements of CONAMA Resolution 23/94 (National Council for the Environment) and controlled by the Brazilian Institute of Environment and Renewable Natural Resources (IBAMA, Brazilian Institute of the Environment and renewable natural resources).

[0018] The expression "environmentally friendly" generally refers to materials and / or substances that can be used in combination with and / or which are compatible with flora, fauna, marine life and / or the like. Ecologically sensitive areas may include freshwater ecosystems, brackish ecosystems (marine coastal zone), temperate ecosystems, polar ecosystems (cold climate regions such as the Arctic and / or Antarctic regions), tropical rainforest ecosystems, wetland ecosystems, arid ecosystems (arid) lands and / or the like It is desirable that environmentally friendly materials and / or substances can have good and / or increased biodegradability and / or low toxicity. Drilling fluids suitable for use in environmentally sensitive areas may also be suitable for use in other, less vulnerable areas. In one aspect, drilling fluids meet and / or exceed the standards set for materials used in the Gulf of Mexico (GMG290000 and TXG330000), for example, for oil drilling in the deep sea coastal zone, as well as standards for acceptability according to CEFAS (Center for Scientific Research in areas of environmental protection, fisheries and aquaculture).

[0019] The hydrocarbon base of a drilling fluid and / or well fluid generally refers to any suitable substance and / or material used in drilling and / or passing through a well and / or tunnel, for example, for the extraction and / or extraction of crude oil, natural gas , bitumen, oil sands, sulfur, other elements, other compounds, other minerals and / or the like. The fluid may be used in rotary drilling and / or the like. Drilling fluids may include fluids, mixtures, emulsions, clay drilling fluids, suspensions and / or the like. Drilling fluids may be predominantly hydrocarbon based and / or predominantly water based.

[0020] The drilling fluid (flushing fluid) may sometimes be referred to as drilling mud, fluid for releasing stuck pipes, a lubricant, circulating fluid, injection fluid, and / or the like. The flushing fluid may lubricate downhole equipment, such as, for example, a drill string and / or drill bit. The drilling fluid may also provide a carrier and / or transport for fragments and / or other residues of cuttings during drilling. The drilling fluid may also form a clay crust to prevent deviation into the host rocks. The drilling fluid may also have an appropriate density to provide hydrolytic stability.

[0021] According to the invention, a drilling fluid is provided that includes linear olefins and oligomers. The drilling fluid may include any suitable amount of a linear olefin, for example, from about 0.1 weight. % to about 60 weight. %, in another aspect, from about 1 weight. % to about 50 weight. %, and in another aspect from about 10 weight. % to about 30 weight. % The remainder of the drilling fluid may include any suitable amount of oligomers.

[0022] In one aspect, the olefin content of the drilling fluid is about 90 weight. % or more, in another aspect, about 92 weight. % or more and in another aspect, about 95 weight. % or more.

[0023] The drilling fluid may also include linear alpha olefins, linear internal olefins, branched olefins, branched internal olefins, esters, water, mineral oils, improved mineral oils, oil-in-water emulsions, water-in-oil emulsions, paraffins, fatty acids or mixtures thereof.

Linear olefins (Olefin component)

[0024] Linear olefins include linear alpha olefins and / or linear internal olefins with the number of carbon atoms in the molecule from about 6 to about 30.

[0025] The term "olefins" generally refers to unsaturated hydrocarbons containing at least one double bond in a molecule. The term "alpha olefins" refers to olefins in which a double bond is located between the terminal and last but one carbon atom, i.e. at the end of the carbon chain, for example, as in oct-1-ene. The expression "internal olefins" refers to olefins in which the double bond is not located at the terminal atom, but between the carbon atoms within the carbon chain, for example, as in oct-3-ene. Olefins can be obtained by any suitable method, for example, oligomerization, metathesis, isomerization, cracking, dehydrogenation and / or the like.

[0026] The expression "linear alpha olefin" refers to an olefin having and / or forming at least a relatively straight and / or unbranched chain (degree of branching up to 50%). In one aspect, the linear alpha olefin may include a molecule of any suitable length and / or any size, for example, with a chain length ranging from about C6 to about C80, in another aspect from about C12 to about C48, in another aspect from about C16 to about C32, in another aspect, from about C16 to about C24, and in another aspect, about C16. Some examples of marketed linear alpha olefins are available from INEOS Oligomers (League City, Texas, U.S.A.) and are known as C14LAO and C1618IO.

[0027] The term "internal olefins" generally refers to olefins with a double bond between non-terminal carbon atoms and / or between carbon atoms within a chain ("internal" carbon atoms). Linear internal olefins include internal olefins from C6 to C30. Examples of internal olefins are oct-3-ene, hex-3-ene and dec-3-ene.

[0028] In one aspect, the linear olefins may include vinylidene isomerized olefins. The term "vinylidene" refers to a structure in which the terminal carbon atom in the double carbon-carbon bond contains two hydrogen atoms and the internal carbon atom contains two alkyl substituted structures. Vinylidene olefins can have a chain of any suitable length, for example, a chain from about C6 to about C48, from about C12 to about C24, from about C16 to about C18, and / or the like. It is desirable, but not necessary, that the vinylidene olefin may include hexadecene.

[0029] Vinylidene olefins can be prepared by any suitable chemical reaction, by any suitable method and / or the like. In one embodiment, a vinylidene olefin can be prepared by dimerizing an appropriate molecule, for example, hex-1-ene, oct-1-ene, dec-1-ene, in the presence of an aluminum alkyl as a catalyst.

[0030] Isomeric olefins can be obtained by any suitable chemical reaction, by any suitable method and / or the like. The term "isomerized" refers to a compound whose structure has been changed and / or rearranged, so that a compound of a different chemical structure, but of the same chemical formula, is obtained. For example, hexadec-1-ene can be isomerized to hexadec-6-ene. In one embodiment, the isomerization catalyst may include metal oxide and / or the like.

Oligomers ("Oligomer component")

[0031] In one aspect, the drilling fluid may contain oligomers that include oligomeric olefins. The term "oligomer" generally refers to molecules and / or compounds containing two or more monomers and / or structural units, for example, from about 2 to about 20, from about 2 to about 10, from about 2 to about 5, less than 5 and / or the like The term "monomer" refers to single molecules, compounds and / or elementary units, for example, such as alpha olefins, linear olefins, linear alpha olefins, internal olefins, linear internal olefins, branched internal olefins, mixtures thereof and / or t .P. The term "dimer" refers to oligomers with two elementary units, the term "trimer" refers to oligomers with 3 elementary units, the term "tetramers" refers to oligomers with 4 elementary units, and the term "pentamers" refers to oligomers with 5 elementary units.

[0032] Oligomers may include monomers with the same chain length and / or mixtures of monomers with different chain lengths. Oligomers can include oligomers derived from monomers with any suitable chain length, for example, from about C4 to about C24, in another aspect from about C4 to about C18, in another aspect from about C4 to about C12, in another aspect from about C6 to about C10, and in another aspect, about C6 or C8.

[0033] Oligomeric olefins may include any suitable molecule and / or any suitable compound, for example, alpha olefins, linear olefins, linear alpha olefins, internal olefins, linear internal olefins, branched internal olefins, mixtures thereof and / or the like .

[0034] The oligomers (oligomeric component) may have any suitable distribution and / or any number of oligomers, such as dimers, trimers, tetramers, heavier oligomers and / or the like. It is desirable, but not necessary, that the oligomeric olefins comprise predominantly dimers, trimers and tetramers of the corresponding monomer, for example, such as hex-1-ene, oct-1-ene, dec-1-ene and / or the like. The term "mainly" refers generally to a large part, for example, one that is greater than at least about 50 weight. %, at least 70 weight. %, at least about 90 weight. % and / or the like

[0035] The ratio of one oligomer to another in a mixture of oligomeric olefins may be any suitable ratio, for example, the ratio of dimer and trimer may be less than about 1: 1, and in another aspect, this ratio may be more than about 1: 1. In one embodiment, the oligomeric olefins may comprise predominantly oct-1-ene dimers and trimers with a dimer to trimer ratio greater than about 1: 1.

[0036] Oligomeric olefins may contain any suitable amount of olefin, for example, at least about 30 weight. % dimer, at least about 60 weight. % dimer, at least about 90 weight. % dimer, and / or the like.

[0037] The ratio of oligomers to each other in a mixture of oligomeric olefins may be any suitable ratio, for example, the ratio of trimer to tetramer may be less than about 1: 1, more than about 1: 1 and / or the like. In one embodiment, the oligomeric olefins may comprise predominantly trimers and tetramers of hex-1-ene with a dimer to trimer ratio of greater than about 1: 1.

[0038] Oligomeric olefins may contain any suitable amount of olefin, for example, at least about 30 weight. % trimer, at least about 40 weight. % trimer, at least about 50 weight. % trimer, and / or the like.

[0039] The term “trisubstituted olefin” generally refers to molecules, compounds and / or components in which a carbon-carbon double bond is attached to three carbon atoms and one hydrogen atom, so that a branched structure usually forms. The oligomeric portion may include any suitable amount of trisubstituted olefins, for example at least about 30 weight. %, in another aspect, at least 50 weight. %, in another aspect, at least 60 weight. %, in another aspect, at least 70 weight. %, in another aspect, at least 80 weight. %, and in another aspect, at least 90 weight. %

[0040] In another aspect, the oligomers may comprise predominantly oct-1-ene dimers and trimers with a ratio of dimers and trimers greater than about 1: 1; however, these oligomers include at least about 90 weight. % dimer; these oligomers mainly include trimers of hex-1-ene with a trimer content above 30 weight. %; these oligomers mainly include trimers of hex-1-ene with a trimer content above 40 weight. %; these oligomers mainly include trimers of hex-1-ene with a trimer content above 50 weight. %

[0041] In another aspect, the drilling fluid may include about 50 weight. % oligomers and 50 weight. % C14 linear olefin; the temperature of the fluidity loss of the drilling fluid is approximately -20 ° C or lower; the temperature of the loss of fluidity of the drilling fluid is approximately -25 ° C or lower; the minimum flash point of the drilling fluid is 120 ° C; the density of the drilling fluid is 0.79-0.82 gram / ml; and the viscosity of the drilling fluid is less than 3 cSt at 40 ° C.

[0042] In another aspect, the drilling fluid may include linear olefins that contain from about 5 weight. % to about 95 weight. % olefins with chain lengths ranging from about C12 to about C48. Oligomers may include at least about 50 weight. % trisubstituted olefins.

[0043] In another aspect, the drilling fluid may have the following distribution of carbon atoms and olefins.

The method of obtaining drilling mud

[0044] A method for producing a drilling fluid comprises oligomerizing olefins with the number of carbon atoms from about 4 carbon atoms to about 24 carbon atoms to form oligomers; and mixing oligomers with linear olefins.

[0045] The method comprises oligomerizing linear alpha olefins, linear internal olefins, branched alpha olefins, branched internal olefins, mixtures thereof and / or the like. The starting material for the oligomerization step may include molecules and / or monomers with any suitable chain length, for example, a chain length of from about C4 to about C24, in another aspect from about C4 to about C12, in another aspect, from about C6 to about C10, and in another aspect, from about C6 to about C8.

[0046] Oligomeric olefins can be obtained by any suitable chemical synthesis, method and / or the like. In one embodiment, oligomeric olefins can be produced and / or they can be formed using acid type catalysts. Acid catalysts may include materials and / or substances with an approximate pH below 7.0, acting as electron acceptors (Lewis acids), and / or the like. The term "catalysts" generally refers to materials and / or substances that alter and / or affect the rate of a chemical reaction and / or conversion, for example, by reducing the activation energy and / or accelerating the reaction. The catalysts may be homogeneous, heterogeneous and / or the like. It is desirable that the catalysts participate in the reaction, but are not spent on it. Oligomerization catalysts may include sulfuric acid, alkylaluminum, metal halides, boron trifluoride and / or the like.

[0047] According to one aspect, in a process using an acid type catalyst, boron trifluoride and a promoter system comprising at least one proton compound (s) or some combination of proton and aprotic promoters are used as a catalyst; butan-1-ol or propan-1-ol are specific examples of proton promoter compounds, and butyl acetate is an example of an aprotic promoter used in combination with an alcohol promoter.

[0048] Acid catalysts such as boron trifluoride promoted by proton cocatalyst, aprotic cocatalyst and mixtures thereof can be used in the oligomerization step. In one aspect, boric trifluoride promoted with an alcohol alkoxylate, such as, for example, 2-methoxyethanol or 1-methoxypropan-2-ol, is used as acid catalysts in the process. At the oligomerization stage, oligomers can be formed with any suitable distribution of molecules and / or compounds, for example, predominantly oct-1-ene dimers and trimers with a dimer to trimer ratio greater than about 1: 1. Preferably, it is not necessary that the process may also include a step for purifying the oligomers so that the dimer content is at least 90 weight. % For purification, any suitable step, method and / or process can be used, for example, distillation, extraction and adsorption.

[0049] In another aspect, oligomers can be formed in the oligomerization step with any suitable distribution of molecules and / or compounds, for example, predominantly trimers and tetramers of hex-1-ene with a trimer to tetramer ratio greater than about 1: 1. Desirably, it is not necessary that the process also include the step of purifying the oligomers so that the trimer content is at least 90 weight. % For purification, any suitable step, method and / or process can be used, for example, distillation, extraction and adsorption. In the process, any of the catalysts may be used depending on the drilling fluids described herein, for example, a heterogeneous solid acid catalyst. The solid acid catalyst may be any suitable material, for example, a polymer resin.

[0050] According to one aspect, in a method using an acid type catalyst, boron trifluoride and a promoter system comprising at least one proton compound (s) or some combination of proton and aprotic promoters are used as a catalyst; butan-1-ol or propan-1-ol are specific examples of proton promoter compounds, and butyl acetate is an example of an aprotic promoter used in combination with an alcohol promoter.

[0051] It is desirable if, at the oligomerization stage, in the presence of solid acid catalysts, oct-1-ene dimers and trimers are predominantly formed and / or obtained with a dimer to trimer ratio greater than about 1: 1. Materials and / or compounds obtained using a solid acid catalyst can also be purified so that the dimer content of the oligomers is at least 90 weight. %

[0052] According to one aspect, the method may also include the step of isomerizing vinylidene olefins. Vinylidene olefins may have a suitable chain length, for example, a chain length of from about C12 to about C24. Desirably, linear olefins are formed during the isomerization process. Vinylidene olefins may include, for example, hexadecene.

[0053] According to one embodiment, the method may also include an aluminum-catalyzed oct-1-ene dimerization step to form vinylidene olefins.

[0054] In one aspect, the method includes providing linear olefins containing from about 5 weight. % to about 95 weight. % olefins with a chain length of from about C12 to about C48. Linear olefins may include at least about 50 weight. % trisubstituted olefins. The method may also include the step of mixing linear olefins with oligomers.

Mud characteristics

[0055] The drilling fluid may have any suitable pour point, for example, at least about 0 ° C or lower, in another aspect, at least about -10 ° C or lower, in another aspect, at least about -15 ° C or lower, in another aspect, at least about -20 ° C or lower, in another aspect, at least about -25 ° C or lower, in another aspect, at least about -30 ° C or lower, in another aspect, at least about -35 ° C or lower, in another aspect, at least about -40 ° C or lower, in another aspect, at least Leray about -45 ° C or lower, and in another aspect at least about -50 ° C or lower. The term "pour point" generally refers to the lowest temperature at which the liquid solidifies and / or continues to flow.

[0056] Linear olefins can have any suitable pour point, for example at least about -10 ° C or lower, in another aspect, at least about -20 ° C or lower, in another aspect, at least about - 30 ° C or lower, in another aspect, at least about -40 ° C or lower, in another aspect, at least about -50 ° C or lower, in another aspect, at least about -60 ° C or lower , and in another aspect, at least about -65 ° C or lower.

[0057] The oligomers can have any suitable pour point, for example at least about 15 ° C or lower, in another aspect, at least about 0 ° C or lower, in another aspect, at least about -9 ° C or lower, and in another aspect, at least about -15 ° C or lower.

[0058] It is desirable, but not necessary, that the linear olefins can act and / or function as a pour point depressant and / or as a lowering agent, for example, to lower the temperature of the fluidity loss of the drilling fluid below the temperature of the fluidity of the individual (pure) other component of the drilling fluid at least about 2 ° C, in another aspect at least 5 ° C, in another aspect at least 10 ° C, and in another aspect at least 20 ° C.

[0059] The drilling fluid may have any suitable viscosity, for example, from about 0.1 centistokes to about 20 centistokes, in another aspect from about 1.0 centistokes to about 10 centistokes, and in another aspect from about 1.4 centistokes to about 6.0 centistokes when measured at 40 ° C.

[0060] In one embodiment, the mud biodegradation index may be less than about 1.0 by definition, see: United States Environmental Protection Agency NPDES 2012 (National Pollution Discharges Elimination System) General Permit for New and Existing Sources and New Discharges in the Offshore Subcategory of the Oil and Gas Extraction Category for the Western Portion of the Outer Continental Shelf of the Gulf of Mexico (GMG290000 and TXG330000) [General authorization for new and existing sources (pollution) and new discharges of oil and gas production objects in the coastal marine zone in the western part of the outer Gulf of Mexico Continental Shelf from NPDES 2012 (National with US EPA (GMG290000 and TXG330000)], Protocol for the Determination of Non-aqueous Major Liquid Degradation by the Closed Vessel Method for Marine Biodegradation Test System, Modified International Standardization Method (ISO, ISO) Method 11734: 1995] . The biodegradation test compares the drilling fluid with a reference sample of internal olefins, in which 65 mole percent are olefins with 16 carbon atoms and 35 mole percent are olefins with 18 carbon atoms.

[0061] The biodegradation index can be determined using the equation below, where the parameters in the numerator and denominator are expressed as a percentage and an acceptable result is 1.054 or less.

[0062] It is desirable that the mud biodegradation index is less than or equal to about 1.0, in another aspect less than or equal to about 0.95, in another aspect less than or equal to about 0.9, and in another aspect less than or equal to about 0.85. Biodegradation can occur by anaerobic routes and / or methods.

[0063] All principles and full contents of U.S. Environmental Protection Agency's Final NPDES 2012 General Permit for New and Existing Sources and New Discharges in the Offshore Subcategory of the Oil and Gas Extraction Category for the Western Portion of the Outer Continental Shelf of the Gulf of Mexico (GMG290000 and TXG330000) [latest General Permission for new and existing sources and new discharges of oil and gas production objects in the coastal marine zone in the Western part of the outer continental shelf of the Gulf of Mexico from the US Environmental Protection Agency (GMG290000 and TXG330000)] with all the additions and / or directions and method 11734: 1995 of the International Organ Standardization annexes are fully incorporated by reference.

[0064] In one aspect, the drilling fluid may have an increased biodegradability of at least about 5 percent compared to the biodegradability of both linear olefins and oligomers alone, in another aspect of at least about 10 percent by compared to the biodegradability of both linear olefins and oligomers alone, in another aspect, by at least about 15 percent compared to the biodegradability of both linear olefins and oligomers alone, in another aspect, at least about 20 percent compared to the biodegradability of both linear olefins and oligomers alone, in another aspect, at least about 25 percent compared to the biodegradability of both linear olefins and oligomers alone, in another aspect, by at least about 30 percent compared to the biodegradability of both linear olefins and oligomers alone.

[0065] In one aspect, the mud toxicity index is less than or equal to about 1.0 as determined by Method E1367-99 of the American Society for Testing Materials (ASTM) Test Protocol, as required by the General Authorization for new and existing sources and new discharges of oil and gas production offshore U.S. Environmental Protection Agency (GMG290000 and TXG330000) NPDES 2012 (National Environmental Pollution Control System) marine area in the western part of the outer continental shelf of the Gulf of Mexico from 10 days Leptocheirus Plumulosus sediment toxicity test for drilling fluids. In this toxicological test, the drilling fluid is compared with a reference sample of internal olefins containing 65 mole percent of C16 olefins and 35 mole percent of C18 olefins.

[0066] The toxicity index can be determined by the equation below based on weight. %, with a value of 1.054 or lower is an acceptable result and LC ₅₀ indicates the concentration in milligrams per liter required to destroy half of the model population of the test subject (organism).

[0067] It is desirable that the mud toxicity index is less than or equal to about 1.0, in another aspect less than or equal to about 0.95, in another aspect less than or equal to about 0.9, and in another aspect less than or equal to about 0.85, and / or the like All principles and the full contents of the description of method E1367-99 of the American Testing Material Testing Protocol are hereby incorporated by reference in their entirety.

[0068] According to one aspect, the drilling fluid can have a reduced toxicity of at least about 5 percent compared to both the toxicity of linear olefins and the toxicity of some oligomers, in another aspect of at least about 10 percent compared to toxicity linear olefins alone, and with the toxicity of certain oligomers, at least about 15 percent compared with the toxicity of linear olefins alone, and with the toxicity of certain oligomers, at least about 20 percent compared with both the toxicity of linear olefins and the toxicity of oligomers alone by at least about 25 percent compared with the toxicity of linear olefins alone and with the toxicity of oligomers alone, and at least about 30 percent compared to with the toxicity of some linear olefins, and with the toxicity of some oligomers.

[0069] According to one aspect, in the absence of any warning of changes, in accordance with the recommendations of OSPAR 2000/4 as amended and supplemented by OSPAR 2008/1, 2010/4 and 2012/5, OCNS classification drilling fluid may be classified as Group D or Group E approved products listed on the full list of the Center for Environmental, Fisheries and Aquaculture Research (CEFAS).

[0070] In one embodiment, the drilling fluid meets the minimum criteria for use in accordance with the requirements of Resolution 23/94 of the National Council for the Environment and under the supervision of the Brazilian Institute for the Environment and Renewable Natural Resources (IBAMA), which includes a biodegradation and toxicity test protocol as defined in the latest General Resolution of the NPDES 2012 (US EPA) for new and existing sources and are new discharges oil and gas facilities in coastal marine area in western outer continental shelf Gulf (GMG290000 and TXG330000), as already mentioned herein.

[0071] Without regard to any theory, it can be said that usually compounds with a higher molecular weight, for example, C18 olefins, have a lower (weaker) biodegradability, since the molecule is larger and the microbe for its cleavage (digestion) it takes more time. Typically, the toxicity index of compounds with a higher molecular weight is higher (greater), since compounds with a small molecular weight decompose into compounds that are toxic when a microbe enters the body. Since large molecules break down to form large residual molecules, it is more difficult for these large molecules to enter the microbe, resulting in a better toxicity indicator.

[0072] It has surprisingly been found that linear olefins mixed with oligomers exhibit increased biodegradation and reduced toxicity. Without being bound by any theory, it can be said that trisubstituted and / or branched molecules can provide many sites for attack and / or cleavage by microbes, which contributes to increased biodegradation, while the residual molecules are large enough to have reduced toxicity.

[0073] Surprisingly, in the case of linear olefins with a large number of carbon atoms in the molecule, containing, for example, at least 20 weight. % C24, “good” biodegradation is observed. It was also unexpected that oligomers with a small number of carbon atoms in a molecule, for example, containing at least 50 weight. % C14 show satisfactory toxicity indices.

[0074] It is desirable that the drilling fluid or the fluid components of the drilling fluid do not include and / or do not contain polycyclic aromatic hydrocarbons and / or polynuclear aromatic hydrocarbons, for example, such as liquid substances obtained in the synthesis process or in the synthesis stages. Linear olefins may include some minimum amount and / or have some minimum content of polycyclic aromatic hydrocarbons and / or polynuclear aromatic hydrocarbons, for example, less than about 0.00001 grams of polycyclic aromatic hydrocarbons per gram of drilling fluid base (level matching the criterion), about 0 grams of polycyclic aromatic hydrocarbons per gram of drilling fluid base as determined by Method 1654A published in Methods for the Determination of Diesel, Mineral and Crude Oils in Offshore Oil and Gas Industry Discharges (Methods for the determination of diesel, mineral oils and crude oil in offshore oil and gas production wastes).

[0075] Similarly, a drilling fluid comprising both linear olefins and oligomers may include or contain a certain minimum amount of polycyclic aromatic hydrocarbons or polynuclear aromatic hydrocarbons, for example, less than about 0.00001 grams per gram of drilling fluid base, about 0 grams of polycyclic aromatic hydrocarbons per gram of drilling fluid base.

[0076] In another aspect, the drilling fluid is characterized by a minimum LC50 value of 30,000 ppm, volumetric ratio for the suspended particulate fraction (SPP) of the drilling fluid in seawater at an exposure of 96 hours, determined on crustaceans Mysidopsis bahia or Mysis relicta, as described in Appendix 2 to Subpart A of Part 435 - Drilling Fluid Toxicity Test (EPA Method 1619) in 40 CFR Part 435.

[0077] In one embodiment, the linear olefins are not isomerized and / or hydrogenated (saturated). Alternatively, the olefins may be isomerized and / or hydrogenated.

EXAMPLES

[0078] The following examples illustrate the preparation and testing of a drilling fluid base using a toxicity enhancing component. The biodegradation index and toxicity index were quantified in comparison with the reference sample and in accordance with the NPDES test protocol as described. The distribution of the number of carbon atoms was analyzed by chromatographic methods. The distribution of olefins was analyzed by nuclear magnetic resonance methods.

EXAMPLE 1

[0079] The product in Example 1A was obtained by oligomerizing oct-1-ene using boron trifluoride as a catalyst and 2-methoxyethanol as a promoter in accordance with Theriot US Pat. No. 5,068,487. The contents and principles set forth in Theriot US Pat. No. 5,068,487 are fully incorporated into this invention by reference. Then, the obtained product was distilled, the unreacted monomer was removed, and the remaining product was collected, and the product designated as Example 1A was obtained. The product from Example 4 was obtained by mixing 50 wt. % of the product from Example 1A and 50 weight. % of the product from Example 2A to form the product Example 4. The product from Example 2A (C14LAO) is a commercial linear alpha olefin from INEOS Oligomers, League City, Texas, U.S.A. Table 1 gives an analysis of the products from Example 1A, Example 2A and their mixture, presented as Example 4.

[0080] Figure 1 presents a histogram of both the toxicity index and the biodegradation index for each of the following products: Example 1A, Example 2A, and Example 4, where a value below 1.054 is considered acceptable or "passing." Unexpectedly, the toxicity index of the product from Example 4 was lower (better) than the toxicity index of both the product from Example 1A and the product from Example 2A. There is also a noticeable improvement in the biodegradation index of the product from Example 4 compared with the predicted degradation index.

[0081] Figure 2 shows dose-response curves for the toxicity of the product from Example 4 and the corresponding reference sample used to calculate the toxicity index according to the above NPDES test protocol. On the dose-response curve for Example 4, it can be seen that the effect (response) better corresponds to probit analysis according to the EPA standard for Eco toxicological calculations.

EXAMPLE 2

[0082] The product from Example 5 was obtained by mixing 20 weight. % of the product from Example 1A and 20 weight. % of the product from Example 2A with 60 weight. % of the product from Example 3 to form the product from Example 5. Materials called Example 2A (C14LAO) and Example 3 (C1618IO) are available from INEOS Oligomers, League City, Texas, U.S.A. Table 2 presents data for the materials used to obtain the product from Example 5.

[0083] Figure 3 shows a histogram of both the toxicity index and the biodegradation index for each of the following products: Example 1A, Example 2A, Example 3, and Example 5, where a value below 1.054 is considered an acceptable or "passing" value. It was unexpectedly found that the toxicity index of the product from Example 5 is better (lower) than the toxicity index of the product from Example 1A and from Example 2A and is similar to the values for the product from Example 3. There is also a noticeable improvement (decrease) in the biodegradation index of the product from Example 5 compared with a predicted degradation index.

EXAMPLE 3

[0084] The product from Example 1B was prepared by oligomerization of oct-1-ene using boron trifluoride as a catalyst and 2-methoxyethanol as a promoter in accordance with Theriot US Pat. No. 5,068,487. The contents and principles set forth in Theriot US Pat. No. 5,068,487 are fully incorporated into this invention by reference. Then, the obtained product was distilled, the unreacted monomer was removed, and the rest of the product was collected, and the product indicated as Example 1B was obtained. The product from Example 6 was obtained by mixing 50 weight. % of the product from Example 1B and 50 weight. % of the product from Example 2B to form the product from Example 6. The material designated as “Example 2B” (C14LAO) is manufactured by INEOS Oligomers, League City, Texas, U.S.A. Table 3 presents the data for the products from Example 1B, Example 2B and from Example 6.

[0085] Figure 4 presents a histogram of both the toxicity index and the biodegradation index for each of the following products: Example 1B, Example 2B, and Example 6, where a value below 1.054 is considered an acceptable or "passing" value. It was unexpectedly found that the toxicity index of the product from Example 6 is lower (better) than the toxicity index of the product from Example 1B and from Example 2B. There is also a noticeable improvement (decrease) in the biodegradation index of the product from Example 6 compared with the predicted degradation index.

EXAMPLE 4

[0086] The products of Example 7, Example 8, and Example 9 were prepared by oligomerizing hex-1-ene in the presence of boron trifluoride as a catalyst and promoter system containing at least one proton compound (s) or a certain combination of proton and aprotic promoters according to the following patents, which illustrate only a small fraction of the many known methods for producing oligomers: see, for example, US patents Nos. 3,682,823; 3,763,244; 3,769,363; 3,780,123; 3,798,284; 3,884,988; 3,097,924; 3,997,621; 4,045,507; and 4,045,508. Butan-1-ol or propan-1-ol are specific examples of proton promoters, and butyl acetate is an example of an aprotic promoter used in combination with an alcohol promoter, such as described in US Pat. No. 3,997,621. Table 4 presents data for 3 products obtained in these processes after distillation of the residues of unreacted monomer. The product from Example 9 was used to obtain both the product from Example 12 and the product from Example 13.

[0087] Figure 5 shows a histogram of both the toxicity index and the biodegradation index for each of the following products: the product from Example 7, the product from Example 8 and the product from Example 9, with a value below 1.054 being considered an acceptable or "passing" value. Surprisingly, products from all three examples showed sediment toxicity that was not expected. Specifically, the product from Example 7, where the sediment toxicity index was significantly lower than suggested on the basis of generally accepted notions. In addition, a clear pattern of data was observed for the data, which was also unexpected.

[0088] The product from Example 12 was obtained by mixing the following components in a ratio of: 20 weight. % of the product from Example 9 and 80 weight. % of the material designated Example 11 (C1618IO) manufactured by INEOS Oligomers in League City, Texas, U.S.A. Table 5 presents data for products used to obtain the product from Example 12.

[0089] Figure 6 shows a histogram for both the toxicity index and the biodegradation index of each of the following products: the product from Example 9, the product from Example 10 and the product from Example 12, with a value below 1.054 being considered an acceptable or "passing" value. It was unexpectedly found that the product from Example 12 in its characteristics exceeded the individual components that make up this mixture.

[0090] The product from Example 13 was obtained by mixing the product from Example 9 (40 wt.%) And the product from Example 10 (C16LAO) (60 wt.%). Table 6 presents the data for the materials used to obtain the product from Example 13. A material called "Example 10" is produced by INEOS Oligomers in League City, Texas, U.S.A.

[0091] Figure 7 shows a histogram for both the toxicity index and the biodegradation index of each of the following products: the product from Example 9, the product from Example 10 and the product from Example 13, with a value below 1.054 being considered an acceptable or "passing" value. It was unexpectedly found that the product from Example 13 in its characteristics exceeded the individual components that make up this mixture.

[0092] The product from Example 14 was obtained by mixing the components in the following ratio: 70 weight. % of the product from Example 7 and 30 weight. % of the material called Example 2C (C 14 LAO) manufactured by INEOS Oligomers in League City, Texas, U.S.A. Table 7 provides data for the materials used to obtain the product from Example 14.

[0093] Figure 8 shows a histogram of the toxicity index of each of the following products: the product from Example 7, the product from Example 2C and the product from Example 14, with values below 1.054 being considered acceptable for the "pass" value. Unexpectedly, it turned out that the product from Example 14 in its characteristics exceeded the individual components that make up this mixture.

[0094] Although the invention disclosed in this application is described using specific options, specific examples and their application, numerous modifications and variations can be made by specialists in this field of technology within the scope of the invention defined by the claims.

Claims (38)

1. A method of obtaining a drilling fluid, including: oligomerization of hex-1-ene with the formation of oligomers, including trimers and tetramers of hex-1-ene with a trimer to tetramer ratio of more than 1: 1 and a trimer content of more than 30 wt.%, the oligomers being formed in the presence of acid type catalysts; and mixing said oligomers with linear olefins, which include linear alpha olefins and / or linear internal olefins with carbon numbers from 6 to 30. 2. The method according to claim 1, wherein the drilling fluid has a pour point of -10 ° C or lower, a biodegradation index of 1.0 or less, a toxicity index of 1.0 or less, a Marine BODIS test score of at least 60%, a flash point of 110 ° C or higher, a viscosity of less than 4 cSt at 40 ° C, a density of 0.78 to 0.83 g / ml and a distribution coefficient in the octanol / water log Pow system of more than 3. 3. The method of claim 1, wherein the drilling fluid comprises from about 0.1 to about 60 wt.% Linear olefins and preferably where the drilling fluid comprises from 1 to 50 wt.% Of linear olefins. 4. The method of claim 1, wherein the linear alpha olefins contain 50 wt.% C14 olefins and the drilling fluid comprises 50 wt.% Of oligomers. 5. The method according to p. 2, in which i) the temperature of the loss of fluidity of the drilling fluid is equal to -20 ° C or lower, such as -25 ° C or lower, or ii) the solution has a flash point of 120 ° C or higher, or iii) the solution has a density of from 0.79 to 0.82 g / ml, or iv) the solution has a viscosity of less than 3 cSt at 40 ° C. 6. The method of claim 1, wherein the acid type catalysts include boron trifluoride promoted by proton cocatalyst, aprotic cocatalyst, or a mixture thereof, and preferably wherein said acid type catalysts include boron trifluoride promoted with alcohol alkoxylate. 7. The method according to p. 1, in which the drilling fluid has a biodegradability exceeding the biodegradability of only these oligomers by at least 20%. 8. The method according to p. 1, in which the drilling fluid has a toxicity reduced by at least 30% as compared with the toxicity of one of the first component of the drilling fluid, and compared with the toxicity of one second component of the drilling fluid. 9. The method according to claim 1, wherein the drilling fluid comprises less than 0.00001 grams of polycyclic aromatic hydrocarbons per gram of drilling fluid base. 10. The method according to claim 1, in which the drilling fluid has a minimum value of LC50 of 30,000 ppm, expressed as the volumetric ratio of suspended fine particles (SPP) in sea water at an exposure of 96 hours, determined using Mysidopsis bahia or Mysis relicta, as described in Appendix 2 to Subpart A of Part 435 - Drilling Fluid Toxicity Test (EPA Method 1619) in 40 CFR Part 435. 11. The method of claim 1, wherein said linear olefins are not isomerized or hydrogenated. 12. A drilling fluid obtained by the method according to claim 1, containing: linear olefins, which include linear alpha olefins and / or linear internal olefins with carbon numbers from 6 to 30; and oligomers that include dimers, trimers, tetramers and / or heavier olefin oligomers, wherein said oligomers include hex-1-ene trimers and tetramers with a trimer to tetramer ratio of more than 1: 1 and a trimer content of more than 30 wt.% and where said oligomers include at least 50 molar percent of a trisubstituted olefin, the drilling fluid has a pour point of -10 ° C or lower, a biodegradation index of 1.0 or lower, a toxicity index of 1.0 or lower, an indicator in the Marine BODIS test of at least 60%, a flash point of 110 ° C or higher, an olefin content of 90 weight % or higher, viscosity less than 4 cSt at 40 ° С, density from 0.78 to 0.83 g / ml and distribution coefficient in the octanol / water log Pow system higher than 3. 13. The drilling fluid according to claim 12, which comprises from 0.1 to 60 wt.% Linear olefins, and preferably which includes from 1 to 50 wt.% Linear olefins. 14. The drilling fluid of claim 12, wherein the linear alpha olefins contain 50% by weight of C14 olefins and which includes 50% by weight of oligomers. 15. The drilling fluid according to claim 12, in which these oligomers include predominantly trimers hex-1-ene, the content of which is more than 40 wt.%. 16. The drilling fluid according to claim 15, wherein said oligomers comprise predominantly hex-1-ene trimers, the content of which is more than 50% by weight. 17. The drilling fluid according to claim 12, which i) has a pour point of −20 ° C. or lower, such as −25 ° C. or lower, or ii) has a flash point of 120 ° C or higher, or iii) has a density of from 0.79 to 0.82 g / ml, or iv) has a viscosity of less than 3 cSt at 40 ° C. 18. The drilling fluid of claim 12, wherein said oligomers are prepared using acidic catalysts, said catalysts comprising boron trifluoride promoted by proton cocatalyst, aprotic cocatalyst or mixtures thereof, and preferably wherein said acid type catalysts include boron trifluoride, promoted by alcohol alkoxylate. 19. The drilling fluid according to claim 12, which has a biodegradability exceeding the biodegradability of said oligomers alone by at least 20%. 20. The drilling fluid according to claim 12, having a toxicity reduced by at least 30% as compared with the toxicity of olefins alone constituting the first component of the drilling fluid, and compared with the toxicity of only oligomers constituting the second component of the drilling fluid. 21. The drilling fluid according to claim 12, which includes less than 0.00001 grams of polycyclic aromatic hydrocarbons per gram of drilling fluid base. 22. A drilling fluid according to claim 12, which has a minimum LC50 value of 30,000 ppm, expressed as the volumetric ratio of the suspended fine particle fraction (SPP) in seawater at an exposure of 96 hours, determined using Mysidopsis bahia or Mysis relicta, as described in Appendix 2 to Subsection A of Part 435 - Drilling Fluid Toxicity Test (EPA Method 1619) in 40 CFR Part 435. 23. The drilling fluid of claim 12, wherein said linear olefins are not isomerized or hydrogenated. 24. The drilling fluid of claim 12, further comprising linear alpha olefins, linear internal olefins, branched olefins, branched internal olefins, esters, water, mineral oils, improved mineral oils, oil-in-water emulsions, water-in emulsions -oil, paraffins, fatty acids or mixtures thereof.

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